Long-term Observational Study of the Longevity, Clinical Quality, and Periodontal Health Impact of Fiber-reinforced Composite Fixed Dental Prostheses.

The goal of this study was to determine the survival rate, success rate, and periodontal health quality (PHQ) of glass fiber-reinforced composite (FRC) resin-bonded fixed dental prostheses (RBFDPs) over an observation period of up to 22 years. RBFDPs reinforced with unidirectional glass fiber strands were fabricated directly (n = 16) or indirectly (n = 31; *n = 1 missing data) for 48 adult patients (24 female, 24 male) and used to replace 39 anterior teeth and 9 posterior teeth in the maxilla (n = 33) or mandible (n = 15) using different framework designs: single-retainer (n = 8), double-retainer (n = 33), or multi-retainer (n = 7). Their fate was classified as a success, functional survival, or failure based on observed complications. PHQ was evaluated by measuring PPD, CAL, SBI, and PI around the abutment teeth and unrestored reference teeth (controls). The clinical quality of the restorations was evaluated according to the Fédération Dentaire Internationale (FDI) criteria. Statistical analysis included Kaplan-Meier survival analysis, Wilcoxon tests, Mann-Whitney U tests, and Chi-squared tests. The significance level was set at P 0.05 for all statistical tests. The outcome was 'failure' in 37 cases (52.9%), 'functional survival' (at a mean follow-up of 9 years) in 15 cases (25.7%), and 'success' in 18 cases (25.7%). The median time to first complication was 32.0 months. The most common complications were debonding and fracture. Multi-retainer FRC-RBFDPs had the highest complication rates. Most FRC-RBFDPs were of good clinical quality according to FDI criteria. PHQ scores showed significantly higher clinical attachment level (CAL) (pw = 0.027) around abutments (3.40 ± 1.42/controls: 3.09 ± 1.11) and significantly greater plaque accumulation around abutments (pw = 0.008, 3.28 ± 1.03/controls: 2.83 ± 1.02) and pontics (pw = 0.001, 3.50 ± 0.99/controls: 2.83 ± 1.02) than around control teeth. Pocket probing depth (PPD) values were lower for abutments (2.43 ± 0.49) than for control teeth (2.52 ± 0.55). The opposite was true for sulcus bleeding index (SBI) scores (abutments: 0.64 ± 0.76/controls: 0.42 ± 0.71). There were no significant differences in periodontal health variables between younger and older restorations. In group comparisons, mean and median PPD, CAL, and plaque index (PI) scores for abutment and control teeth were higher in older patients than in younger patients. Based on our survival and complication data, FRC-RBFDPs can be considered short- to medium-term restorations. A 5-year survival rate of approximately 80% can be expected. The most common complications were reparable defects. Thus, repairs can prolong the survival time in many cases. Patient age had a greater effect on PHQ than restoration age. For example, FRC-RBFDPs in older patients were associated with higher levels of plaque accumulation and gingival inflammation around abutments, suggesting that older patients have greater difficulty cleaning the resin-bonded bridge area.